silverstripe-framework/docs/en/topics/controller.md

Controller

Base controller class. You will extend this to take granular control over the actions and url handling of aspects of your SilverStripe site.

Usage

The following example is for a simple [api:Controller] class. If you're using the cms module and looking at Page_Controller instances you won't need to setup your own routes since the cms module handles these routes.

mysite/code/Controllers/FastFood.php

:::php
<?php

class FastFood_Controller extends Controller {
	
	private static $allowed_actions = array('order');
	
	public function order(SS_HTTPRequest $request) {
		print_r($request->allParams());
	}
}

Routing

mysite/_config/routes.yml

:::yaml
---
Name: myroutes
After: framework/routes#coreroutes
---
Director:
  rules:
    'fastfood//$Action/$ID/$Name': 'FastFood_Controller'

Request for /fastfood/order/24/cheesefries would result in the following to the $arguments above. If needed, use ?flush=1 on the end of request after making any code changes to your controller.

:::ss
Array
(
    [Action] => order
    [ID] => 24
    [Name] => cheesefries
)

SilverStripe automatically adds a URL routing entry based on the controller's class name, so a `MyController` class is accessible through `http://yourdomain.com/MyController`.

Access Control

Through $allowed_actions

All public methods on a controller are accessible by their name through the $Action part of the URL routing, so a MyController->mymethod() is accessible at http://yourdomain.com/MyController/mymethod. This is not always desireable, since methods can return internal information, or change state in a way that's not intended to be used through a URL endpoint.

SilverStripe strongly recommends securing your controllers through defining a $allowed_actions array on the class, which allows whitelisting of methods, as well as a concise way to perform checks against permission codes or custom logic.

:::php
class MyController extends Controller {
	
	private static $allowed_actions = array(
		// someaction can be accessed by anyone, any time
		'someaction', 
		// So can otheraction
		'otheraction' => true, 
		// restrictedaction can only be people with ADMIN privilege
		'restrictedaction' => 'ADMIN', 
		// complexaction can only be accessed if $this->canComplexAction() returns true
		'complexaction' '->canComplexAction' 
	);
}

There's a couple of rules guiding these checks:

• Each class is only responsible for access control on the methods it defines
• If $allowed_actions is an empty array or undefined, only the index action is allowed
• Access checks on parent classes need to be overwritten via the Config API
• Only public methods can be made accessible
• If a method on a parent class is overwritten, access control for it has to be redefined as well
• An action named "index" is whitelisted by default, unless allowed_actions is defined as an empty array, or the action is specifically restricted in there.
• Methods returning forms also count as actions which need to be defined
• Form action methods (targets of FormAction) should NOT be included in $allowed_actions, they're handled separately through the form routing (see the "forms" topic)
• $allowed_actions can be defined on Extension classes applying to the controller.

If the permission check fails, SilverStripe will return a "403 Forbidden" HTTP status. You can overwrite the default behaviour on undefined $allowed_actions to allow all actions, by setting the RequestHandler.require_allowed_actions config value to false (not recommended).

Through the action

Each method responding to a URL can also implement custom permission checks, e.g. to handle responses conditionally on the passed request data.

:::php
class MyController extends Controller {
	
	private static $allowed_actions = array('myaction');
	
	public function myaction($request) {
		if(!$request->getVar('apikey')) {
			return $this->httpError(403, 'No API key provided');
		} 
			
		return 'valid';
	}
}

Unless you transform the response later in the request processing, it'll look pretty ugly to the user. Alternatively, you can use ErrorPage::response_for(<status-code>) to return a more specialized layout.

Note: This is recommended as an addition for $allowed_actions, in order to handle more complex checks, rather than a replacement.

Through the init() method

After checking for allowed_actions, each controller invokes its init() method, which is typically used to set up common state in the controller, and include JavaScript and CSS files in the output which are used for any action. If an init() method returns a SS_HTTPResponse with either a 3xx or 4xx HTTP status code, it'll abort execution. This behaviour can be used to implement permission checks.

:::php
class MyController extends Controller {
	
	private static $allowed_actions = array();
	
	public function init() {
		parent::init();
		if(!Permission::check('ADMIN')) return $this->httpError(403);
	}
}

URL Handling

In the above example the URLs were configured using the [api:Director] rules in the routes.yml file. Alternatively you can specify these in your Controller class via the $url_handlers static array (which gets processed by the [api:RequestHandler]).

This is useful when you want to subvert the fixed action mapping of fastfood/order/* to the function order. In the case below we also want any orders coming through /fastfood/drivethrough/ to use the same order function.

mysite/code/Controllers/FastFood.php

:::php
class FastFood_Controller extends Controller {

    private static $allowed_actions = array(
	'drivethrough'
    );

    private static $url_handlers = array(
        'drivethrough/$Action/$ID/$Name' => 'order'
    );

URL Patterns

The [api:RequestHandler] class will parse all rules you specify against the following patterns.

A rule must always start with alphabetical ([A-Za-z]) characters or a $Variable declaration

Pattern	Description
$	Param Variable - Starts the name of a paramater variable, it is optional to match this unless ! is used
!	Require Variable - Placing this after a parameter variable requires data to be present for the rule to match
//	Shift Point - Declares that only variables denoted with a $ are parsed into the $params AFTER this point in the regex

Examples

See maetl's article in the Links below of a detailed explanation.

$Action/$ID/$OtherID - Standard URL handler for a Controller. Take whatever URLSegment it is set to, find the Action to match a function in the controller, and parse two optional $param variables that will be named ID and OtherID.

admin/help//$Action/$ID - Match an url starting with /admin/help/, but don't include /help/ as part of the action (the shift point is set to start parsing variables and the appropriate controller action AFTER the //)

tag/$Tag! - Match an URL starting with /tag/ after the controller's URLSegment and require it to have something after it. If the URLSegment is order then /order/tag/34 and /order/tag/asdf match but /order/tag/ will not

You can use the debug_request=1 switch from the urlvariabletools to see these in action.

Redirection

Controllers facilitate HTTP redirection.

Note: These methods have been formerly located on the [api:Director] class.

• redirect("action-name"): If there's no slash in the URL passed to redirect, then it is assumed that you want to go to a different action on the current controller.
• redirect("relative/url"): If there is a slash in the URL, it's taken to be a normal URL. Relative URLs will are assumed to be relative to the site-root.
• redirect("http://www.absoluteurl.com"): Of course, you can pass redirect() absolute URLs too.
• redirectBack(): This will return you to the previous page.

The redirect() method takes an optional HTTP status code, either 301 for permanent redirects, or 302 for temporary redirects (default).

Access control

You can also limit access to actions on a controller using the static $allowed_actions array. This allows you to always allow an action, or restrict it to a specific permission or to call a method that checks if the action is allowed.

For example, the default Controller::$allowed_actions is

private static $allowed_actions = array(
	'handleAction',
	'handleIndex',
);

which allows the handleAction and handleIndex methods to be called via a URL.

To allow any action on your controller to be called you can either leave your $allowed_actions array empty or not have one at all. This is the default behaviour, however it is not recommended as it allows anything on your controller to be called via a URL, including view-specific methods.

The recommended approach is to explicitly state the actions that can be called via a URL. Any action not in the $allowed_actions array, excluding the default index method, is then unable to be called.

To always allow an action to be called, you can either add the name of the action to the array or add a value of true to the array, using the name of the method as its index. For example

private static $allowed_actions = array(
	'MyAwesomeAction',
	'MyOtherAction' => true
);

To require that the current user has a certain permission before being allowed to call an action you add the action to the array as an index with the value being the permission code that user must have. For example

private static $allowed_actions = array(
	'MyAwesomeAction',
	'MyOtherAction' => true,
	'MyLimitedAction' => 'CMS_ACCESS_CMSMain',
	'MyAdminAction' => 'ADMIN'
);

If neither of these are enough to decide if an action should be called, you can have the check use a method. The method must be on the controller class and return true if the action is allowed or false if it isn't. To do this add the action to the array as an index with the value being the name of the method to called preceded by '->'. You are able to pass static arguments to the method in much the same way as you can with extensions. Strings are enclosed in quotes, numeric values are written as numbers and true and false are written as true and false. For example

private static $allowed_actions = array(
	'MyAwesomeAction',
	'MyOtherAction' => true,
	'MyLimitedAction' => 'CMS_ACCESS_CMSMain',
	'MyAdminAction' => 'ADMIN',
	'MyRestrictedAction' => '->myCheckerMethod("MyRestrictedAction", false, 42)',
	'MyLessRestrictedAction' => '->myCheckerMethod'
);

In this example, MyAwesomeAction and MyOtherAction are always allowed, MyLimitedAction requires access to the CMS for the current user and MyAdminAction requires the current user to be an admin. MyRestrictedAction calls the method myCheckerMethod, passing in the string "MyRestrictedAction", the boolean false and the number 42. MyLessRestrictedAction simply calls the method myCheckerMethod with no arguments.

API Documentation

[api:Controller]

Links

• [api:Director] class
• execution-pipeline
• URL Handling in Controllers by maetl